Many individuals suffering from neurological disorders, balance dysfunction, difficulty with weight shifting, and loss of proprioception, have problems maintaining their center of gravity (“COG”) over their base of support, the perimeter defining the contact region surrounding the feet. The inability to maintain one's COG over the base of support results in decreased postural and motor control in sitting, standing, changing positions, and locomotion. Maintenance of the COG over the base of support is desirable for smooth and coordinated movement in balance and gait.
The ability to maintain COG balance over the base of support relies in part on three input systems: the somatosensory (proprioceptive and tactile input from the torso, feet, and ankles); the vestibular (spatial orientation and balancing functioning); and the visual (input from sight). When a problem occurs in one of these input systems, it may affect both the input to the sensory integration system of the central nervous system (“CNS”) and the resulting ability to use the remaining one or more of the somatosensory, vestibular, or visual input systems for balance. The CNS may then tend to rely more heavily on one input system relative to another, or even to rely on other areas of the nervous system itself.
The nervous system's reliance on other areas of the CNS to compensate for the deficiency of one input system can lead to nervous system fatigue. In addition, problems associated with ineffective or inaccurate input or output tend to affect motor control, speed, movement coordination, automatic postural reaction, ability to control one's COG over their base of support, weight shifting, and equal weight bearing. Alterations in input, central processing, and output systems vary with age, with the type and severity of the neurological problem, and with the severity of any resulting neurological degeneration.
Proper coordination of posture and movement rely on the body's ability to initiate and effect subtle postural adjustments. For example, one's ability to remain in an upright position while sitting or standing is fundamental to safe and efficient movement. Similarly, balance control while walking requires proactive control of upper body stability in both the sagittal and frontal planes, as well as the coordination of the upper and lower extremities. Such control is often compromised due to various neurological disorders. Correction of aberrant balance is often complicated by the biomechanics of certain movements.
For example, two thirds of a human's body weight is centered in the upper body (head, torso, and arms). When the body mass is not neutral, or is off-center, the center of gravity is not positioned over the base of support. This is simply a natural instability due to the anatomy of a human being. However, when a person cannot maintain control over this natural instability, decreased ability in function, coordination, balance and ambulation tend to occur. To ameliorate and/or eliminate this instability and facilitate better movement, I have found that providing certain counterbalances and proprioceptive cues to a person having such a problem tends to overcome upper body instability.